CHALLENGER LIMPS INTO A LOW ORBIT AS AN ENGINE FAILS

By WILLIAM J. BROAD, Special to the New York Times

Published: July 30, 1985

Correction Appended

CAPE CANAVERAL, Fla., July 29—
A main engine of the space shuttle Challenger failed today 5 minutes and 45 seconds into its flight, but the crew was declared safe as the craft limped into a low orbit about the earth.

It was the first major malfunction during ascent in the 19 flights of the shuttle program.

''They have gone on orbit,'' said Richard N. Richards of mission control in Houston as the spacecraft began to circle the earth. ''At the present time there is no plan to come home. They intend to seek a nominal mission duration. The crew is safe. There is no plan to come home.''

Jesse W. Moore, who heads of the shuttle program for the National Aeronautics and Space Administration, said: ''We are pretty optimistic about achieving all the goals of the mission.'' #190-Mile Orbit Sought At a later news briefing, space agency officials said the small thruster jets on the shuttle would be used to try to bring the spacecraft to an orbit of about 190 miles. ''The crew was relieved once we told them we were looking at a full-duration flight,'' Cleon Lacefield, the flight director, said from Houston.

Asked if many questions needed to be answered before another shuttle launching was attempted, Mr. Lacefield said: ''I think we need to go back and look at the failures we have sustained today, and make sure that we understand what those failures are before we go into another ascent.'' The space shuttle Discovery is scheduled to be launched in late August.

After a delayed liftoff from the Kennedy Space Center here at 5 P.M., the Challenger roared through the cloudy Florida sky and into space, its two large solid-fueled rockets soon falling away. Then, nearly 6 minutes into the flight, when everything seemed safe and secure, the No. 1 engine of the shuttle's three main engines failed. In all, it should have fired for about 9 minutes.

An 'Abort to Orbit'

Ground controllers called an ''abort to orbit,'' prompting a collective gasp from spectators and reporters who had gathered to watch the launching.

The shuttle then managed to drag itself into a lower-than-planned orbit with the two engines remaining. The noncircular orbit was about 170 miles at its highest point, shy of its goal of 240 miles.

Officials said the orbit was high enough so that it would not decay, forcing the shuttle to re-enter the earth's atmosphere unexpectedly.

Mr. Lacefield said that if the engine failure had occurred 33 seconds earlier, the Challenger would have been forced to land at its trans-Atlantic abort site, an American Air Force base in Zaragoza, Spain.

Mr. Moore played down the problems, saying ''abort'' was too strong a word to describe the events. ''We ought to purge the words 'abort to orbit' as long as we get into orbit,'' he said.

Cause of Failure Not Known

Mission scientists were seeking to find out why the No. 1 engine failed. They said that some data radioed to ground controllers indicated that it was overheating but that they were not sure if those readings were correct.

The Challenger's mission had been delayed until today because of valve problems in a different engine, the No. 2, more than two weeks ago.

''We will be looking very intensively at the flight data from those engines,' Mr. Moore said at a news conference. The shuttle's main engines are built by the Rocketdyne Division of Rockwell International.

Asked if the problems would reflect poorly on the space agency, Mr. Moore said ''the system exhibited its design capability'' in coping with the engine failure.

He went on: ''I see no impacts to NASA's reputation because of that. Anybody who operates in this launch business is going to have some anomalies along the way. There's no question about it. You just have to put a design philosophy in place and a system in place that can cope with certain anomalies. I think we have that in the shuttle program.''

The launching today was carried out under the usual countdown procedures and did not rely on looser launching criteria that space agency officials are talking about putting into place.

Space agency spokesmen said ground controllers first considered bringing the $1.2 billion winged spaceship back to an early landing after a few orbits. But later they decided the shuttle had enough fuel in its Orbital Maneuvering System engines to probably achieve the intended orbit. These engines are smaller than the main shuttle engines and are used for in-flight maneuvers.

A higher orbit is desired for achieving some of the scientific goals of on the shuttle mission.

The Challenger's mission is to study the earth, sun and stars with some of the largest and most sophisticated instruments even taken into space.

Delay in Liftoff

The flight is the eighth for the Challenger. The troubled liftoff also marked the beginning of the 50th mission in the history of the manned American space program. The first was Alan B. Shepard's suborbital flight in 1961.

The Challenger's flight planned for July 12 was scrubbed just seconds before liftoff because of the problem with the No. 2 main engine.

Today's liftoff was also delayed for nearly two hours when a navigational device on one of the shuttle's two solid-rocket boosters failed. Each solid rocket has three of these gyroscopes, which keep the engines of the solid rockets pointed in the right direction and compensate for high winds and other problems encountered in the shuttle's ascent.

Correction: July 31, 1985, Wednesday, Late City Final Edition A front-page diagram yesterday on the launching of the space shuttle Challenger incorrectly labeled the actual and planned orbits during its first hours in space. The actual orbits ranged from 123 miles to 170 miles; the planned orbit was 240 miles.